Subscribe to the latest research through IGI Global's new InfoSci-OnDemand Plus

InfoSci®-OnDemand Plus, a subscription-based service, provides researchers the ability to access full-text content from over 100,000 peer-reviewed book chapters and 26,000+ scholarly journal articles covering 11 core subjects. Users can select articles or chapters that meet their interests and gain access to the full content permanently in their personal online InfoSci-OnDemand Plus library.

Encyclopedia of Information Science and Technology, Fourth Edition (10 Volumes) Now 50% Off

Take 50% off when purchasing the Encyclopedia directly through IGI Global's Online Bookstore. Plus, receive the complimentary e-books for the first, second, and third editions with the purchase of the Encyclopedia of Information Science and Technology, Fourth Edition e-book.

InfoSci®-Journals Annual Subscription Price for New Customers: As Low As US$ 5,100

This collection of over 175 e-journals offers unlimited access to highly-cited, forward-thinking content in full-text PDF and XML with no DRM. There are no platform or maintenance fees and a guarantee of no more than 5% increase annually.

What is Inverted Index

An inverted index is an index into a set of documents of the words in the documents. The index is accessed by some search method. Each index entry gives the word and a list of documents, possibly with locations within the documents, where the word occurs. The inverted index data structure is a central component of a typical search engine indexing algorithm. A goal of a search engine implementation is to optimize the speed of the query: find the documents where word X occurs. Once a forward index is developed, which stores lists of words per document, it is next inverted to develop an inverted index. Querying the forward index would require sequential iteration through each document and to each word to verify a matching document. The time, memory, and processing resources to perform such a query are not always technically realistic. Instead of listing the words per document in the forward index, the inverted index data structure is developed, which lists the documents per word. With the inverted index created, the query can now be resolved by jumping to the word ID (via random access) in the inverted index. Random access is generally regarded as being faster than sequential access.
Learn more in:
Improving the Quality of Web Search